Solve for $k$ : $-16 = -8 + k$
Solution: Add $8$ to both sides: $ \begin{eqnarray} \\ \hphantom{-16 {+ 8}} &\hphantom{=}& \hphantom{k} \\ -16 &=& -8 + k \\ \\ {+8} && {+8} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ -16 {+ 8} &=& k \\ \end{eqnarray} $ Simplify. $ k = -8$